A novel Gram-stain positive, facultatively anaerobic, motile, irregularly rod-shaped bacterium, designated GY 10621T, was isolated from rhizosphere soil of Spartina alterniflora in Beihai City, Guangxi Province, PR China, and characterized using a polyphasic taxonomic approach. GY 10621T was positive for catalase and oxidase. Growth occurred at 4-42 °C (optimum 30-37 °C), at pH 5.0-9.0 (optimum pH 7.0) and in the presence of 0-5% NaCl (w/v) (optimum 1-3%). The main menaquinones were MK-9 (H4) (92.2 %) and MK-10 (7.8 %). The major cellular fatty acids were anteiso-C15 : 0 and C14 : 0. The peptidoglycan was the type A4α (l-Lys-Ser-d-Glu). The polar lipids included four phosphoglycolipids, four glycolipids, an unidentified lipid and six unidentified phospholipids. The DNA G+C content of the type strain was 71.7 mol%. On the basis of the results of 16S rRNA gene analysis, the type strain of a species with a validly published name with the highest similarity to GY 10621T was Flavimobilis soli KCTC 13155T (97.16 %), followed by Sanguibacter suarezii NBRC 16159T (96.39 %). The calculated results indicated that compared with GY 10621T, the average nucleotide identity (ANI) values of three strains closely related to GY 10621T (the two aforementioned type strains and 'S. massiliensis' Marseille-P3815) were 74.18-94.97 %, and the digital DNA-DNA hybridization (dDDH) values were 20.3-60.6 %. The results of 16S rRNA-based and genome-based phylogenetic tree analysis indicated that GY 10621T should be assigned to the genus Flavimobilis. On the basis of evidence from polyphasic studies, GY 10621T should be designated as representing a novel species of the genus Flavimobilis, for which the name Flavimobilis rhizosphaerae sp. nov. is proposed. The type strain is GY 10621T (=CGMCC 1.17411T=KCTC 49515T).
Keywords: Flavimobilis; Spartina alterniflora; novel species; rhizosphere soil.